Start here
A few places to begin, from the aircraft’s story to the people who fly it.
Meet the aircraft
The Czech-built U15 Phoenix combines a low wing, side-by-side cockpit and fixed tailwheel landing gear. Its long wing can be shortened by exchanging the tips, allowing the same aircraft to serve touring and soaring roles. VSKYLABS represents the piston-powered U15 in separate X-Plane 11 and 12 products. The developer describes the project as approved by Phoenix Air while remaining an independent simulation.
Aircraft background
VSKYLABS · Read more ↗Long and short Phoenix wing tips
VSKYLABS represents the piston-powered Phoenix with interchangeable long and short wing tips. Separate native editions are available for X-Plane 11 and 12.
U15 Phoenix · VSKYLABS · X-Plane 11 · X-Plane 12
VSKYLABS · Read more ↗Into the cockpit
YouTube Andre Sosinski · 7 min ·
Touring Motor Glider (TMG) soaring flight of the Phoenix U15
An engine-off thermalling flight in the Phoenix U15 touring motor glider.
Real aircraft · Phoenix Air U15 Phoenix
Watch on YouTube ↗Preview images are served by AirframeDB. Videos open on YouTube only when you choose to watch.
Meet Phoenix Air U15 Phoenix
The Czech-built U15 Phoenix combines a low wing, side-by-side cockpit and fixed tailwheel landing gear. Its long wing can be shortened by exchanging the tips, allowing the same aircraft to serve touring and soaring roles.
VSKYLABS represents the piston-powered U15 in separate X-Plane 11 and 12 products. The developer describes the project as approved by Phoenix Air while remaining an independent simulation.
Phoenix Air U15 Phoenix
Aircraft type designators
Use the code for the model you are flying. The linked authority lists the applicable aircraft.
History & design
One airframe, two wing arrangements
Martin Stepanek’s Phoenix Air U15 was developed in the Czech Republic as a two-seat motor glider. Its interchangeable tips allow the same composite aircraft to adopt a longer soaring wing or a shorter touring configuration.
VSKYLABS · VSKYLABS Aerospace Simulations Aircraft Center: VSKYLABS Phoenix Air U15 S-LSA ↗Phoenix Air U15 and VSKYLABS wing configurations
The two configurations in X-Plane
VSKYLABS dates its independent U15 project to 2017. The add-on includes separate 15 m and 11 m wing flight models, rather than treating the tips solely as a visual option.
VSKYLABS · VSKYLABS Aerospace Simulations Aircraft Center: VSKYLABS Phoenix Air U15 S-LSA ↗Phoenix Air U15 and VSKYLABS wing configurations
Systems & details
Why the tip choice matters
The developer describes the short-wing configuration as faster in cruise and quicker in roll, while the extended wing serves the motor-glider role. The selected wing therefore belongs in any comparison of handling. A T-tail, side-by-side cockpit and conventional fixed gear complete a design intended to move between powered touring and soaring.
In your simulator
Systems, equipment and documentation for each developer’s aircraft.
X-Plane 11 · X-Plane 12U15 Phoenix
VSKYLABS · Released
U15 Phoenix
VSKYLABS · Released
Manuals & resources
Find your next read
Choose a topic for a short introduction and a link to the original source. Simulator references identify the developer and edition they cover.
Simulator documentation
Long and short Phoenix wing tipsU15 Phoenix · VSKYLABS · X-Plane 11 · X-Plane 12
VSKYLABS represents the piston-powered Phoenix with interchangeable long and short wing tips. Separate native editions are available for X-Plane 11 and 12.
Official developer / designated-store reference · checked 2026-09-14
VSKYLABS · Read the source ↗Read the original documentation from the people who created it. Manuals open on their publisher’s website.
Developer documentation
VSKYLABS Aerospace Simulations Aircraft Center: VSKYLABS Phoenix Air U15 S-LSAVSKYLABS · Official developer / designated-store reference · checked 2026-09-14 VSKYLABS Phoenix Air U15 S-LSA add-on for X-Plane Flight Simulator.VSKYLABS · Official developer / designated-store reference · checked 2026-09-14Type designator
ICAO Doc 8643 — aircraft type designatorsInternational Civil Aviation Organization · Public search data retrieved 2026-09-14; authority update 2026-09-03Built-in force-feedback profiles
Read the documentary basis, editable starting settings and remaining questions for the aircraft you fly. Each explanation refers to the exact profile revision shown.
Catalogue programme-20261022-v1 · 3 profile choices
VSKYLABS Phoenix Air U15 15m
VSKYLABS · Free and Pro · Revision 3 · Inherited starting point
X-Plane 12
VSKYLABS Phoenix Air U15 15m: Mechanical linkage motivates reversible stick loading.
VSKYLABS Phoenix Air U15 11m Cruiser
VSKYLABS · Free and Pro · Revision 3 · Inherited starting point
X-Plane 12
VSKYLABS Phoenix Air U15 11m Cruiser: Mechanical linkage motivates reversible stick loading.
Phoenix Air U15 Phoenix
Free and Pro · Revision 1 · Partial review
X-Plane 12 · X-Plane 11
Phoenix Air U15 Phoenix: Mechanical linkage motivates reversible stick loading.
Phoenix Air U15 Phoenix
Phoenix Air U15 Phoenix: Mechanical linkage motivates reversible stick loading.
Aircraft and simulator scope
- Phoenix Air U15 Phoenix · X-Plane 12 · family starting point
- Phoenix Air U15 Phoenix · X-Plane 11 · family starting point
Phoenix Air U15 Phoenix · Family sources identify only the variants and product versions described above.
The simulator model and controls
The Czech-built U15 Phoenix combines a low wing, side-by-side cockpit and fixed tailwheel landing gear. Its long wing can be shortened by exchanging the tips, allowing the same aircraft to serve touring and soaring roles.
This starting point selects Phoenix Air U15 Phoenix. Its aircraft-level settings do not select a particular developer’s custom systems.
How this profile feels
Mechanical linkage motivates reversible stick loading. Spring resistance builds with the selected airspeed response. A separate aerodynamic term adds speed-dependent control load.
Trim is documented, while the selected source does not establish its linkage to stick neutral. Valid trim provides the configured pressure relief. Autopilot following is off.
Controls and trim
The Phoenix has push-pull pitch/roll controls and a cable rudder, with interchangeable long glider and short touring wingtips. Engine-off soaring, propeller feathering, flaps and spoilers belong to its motor-glider configuration.
About the values
The gains are normalized profile settings. They describe the chosen effect balance; hand force depends on the device and its output limits. IAS references are tuning values rather than operating limits. Physical acceptance of this revision remains pending.
What the documentation establishes
Recovered developer source identifies U15 Rotax motor glider, separate from electric D14.
Developer lists fixed conventional gear and interchangeable 15m/11m wing configurations.
Documentary review and sources
These decisions describe the documentary basis and remaining gaps for this revision. Aircraft documentation and a starting setting describe different kinds of evidence.
Aircraft and variant
ReviewedThis starting point selects Phoenix Air U15 Phoenix. Its aircraft-level settings do not select a particular developer’s custom systems.
Flight controls
Not yet reviewedThe Phoenix has push-pull pitch/roll controls and a cable rudder, with interchangeable long glider and short touring wingtips. Engine-off soaring, propeller feathering, flaps and spoilers belong to its motor-glider configuration.
Trim
Not yet reviewedTrim is documented, while the selected source does not establish its linkage to stick neutral. Pitch authority 0.3 provides load relief and permitted centre movement; roll authority is 0.1.
Autopilot and stability
Not yet reviewedAutopilot following is off; the configured spring and load retain the hardware feel.
Equipment
ReviewedGear, flap and ground cues follow the selected settings and available simulator-reported states.
Speeds and limits
Not yet reviewedThe indicated-speed references set the profile response scale; they are separate from aircraft operating limits.
Simulator integration
Not yet reviewedThe profile targets xplane12, xplane11. Add-on-specific controls use only the supported references configured by this profile.
Force-feedback settings
Not yet reviewedThe settings define the profile’s effect balance. Device output limits affect physical hand force.
Starting settings and their rationale
These configured values are starting estimates. The explanations describe what each setting controls; physical validation appears separately below.
| Setting | Starting value | What it controls and why |
|---|---|---|
| Spring strength | Starting value0.64 | What it controls and whyMechanical linkage motivates reversible stick loading. The baseline spring is 0.64. Its low-speed blend reaches baseline strength at 35 KIAS. |
| Master force gain | Starting value0.85 | What it controls and whyScales overall profile strength while preserving effect balance, subject to device and output limits. |
| Profile force gain | Starting value1 | What it controls and whyThe aerodynamic-load gain is 1 with an indicated-speed reference of 70 KIAS. This supplies speed-dependent loading alongside the spring. |
| Force tuning speed/reference | Starting value70.0 kt | What it controls and whySets the IAS reference for aerodynamic loading. It is an estimate, not published cruise TAS or a flight limit. |
| Spring response reference speed | Starting value35.0 kt | What it controls and whySets the IAS where the low-speed blend reaches baseline strength; high-speed stiffening also uses it. |
| Aileron force scale | Starting value0.6 | What it controls and whyRoll and pitch aerodynamic scales are 0.6 and 0.78, respectively. They set the aerodynamic axis balance. No custom spring-travel curve is enabled. |
| Elevator force scale | Starting value0.78 | What it controls and whyScales pitch aerodynamic loading; pitch spring travel and trim responses are separate settings. |
| Trim feel | Starting valueEnabled | What it controls and whyRetained for compatibility and group membership. Trim relief, rather than this flag, controls centre movement. |
| Trim relief | Starting valueEnabled | What it controls and whyAllows trim relief with supported control law and valid telemetry. Axis authorities set its amount. |
| Autopilot follow | Starting valueDisabled | What it controls and whyAutopilot following is off; the configured spring and load retain the hardware feel. |
| Autopilot neutral hold | Starting valueDisabled | What it controls and whyPermits centering hold during a supported AP state, separate from following a moving target. |
| Output force limit | Starting value0.55 | What it controls and whyCaps directed-force output. Native spring effects and device limits remain separate. |
All 44 starting settings and their rationale
The settings define the profile’s effect balance. Device output limits affect physical hand force.
| Setting | Starting value | What it controls and why |
|---|---|---|
| Spring strength | Starting value0.64 | What it controls and whyMechanical linkage motivates reversible stick loading. The baseline spring is 0.64. Its low-speed blend reaches baseline strength at 35 KIAS. |
| Spring deadband | Starting value0.04 | What it controls and whySets travel around the centre before the baseline spring resists. Smaller values engage it sooner. |
| Profile force gain | Starting value1 | What it controls and whyThe aerodynamic-load gain is 1 with an indicated-speed reference of 70 KIAS. This supplies speed-dependent loading alongside the spring. |
| Master force gain | Starting value0.85 | What it controls and whyScales overall profile strength while preserving effect balance, subject to device and output limits. |
| QBlend Enabled | Starting valueEnabled | What it controls and whyAllows baseline spring strength to rise with indicated airspeed where the control law permits it. |
| QSpring Minimum Factor | Starting value0.4 | What it controls and whySets low-speed spring strength as a fraction of baseline when blending is enabled. One keeps full strength. |
| QSpring Start Knots | Starting value9.8 kt | What it controls and whySets the IAS where the low-speed spring blend starts rising. This is a feel threshold, not a flight limit. |
| Spring response reference speed | Starting value35.0 kt | What it controls and whySets the IAS where the low-speed blend reaches baseline strength; high-speed stiffening also uses it. |
| Force tuning speed/reference | Starting value70.0 kt | What it controls and whySets the IAS reference for aerodynamic loading. It is an estimate, not published cruise TAS or a flight limit. |
| Airspeed spring stiffening gain | Starting value0.3 | What it controls and whyThe high-speed spring-stiffening gain is 0.3. It strengthens the permitted spring response above 35 KIAS, with the squared-speed ratio capped at 5. |
| Airspeed spring stiffening limit | Starting value5 | What it controls and whyLimits the squared airspeed ratio used for high-speed spring stiffening; it is not a device-force cap. |
| Aileron force scale | Starting value0.6 | What it controls and whyRoll and pitch aerodynamic scales are 0.6 and 0.78, respectively. They set the aerodynamic axis balance. No custom spring-travel curve is enabled. |
| Elevator force scale | Starting value0.78 | What it controls and whyScales pitch aerodynamic loading; pitch spring travel and trim responses are separate settings. |
| Output force limit | Starting value0.55 | What it controls and whyCaps directed-force output. Native spring effects and device limits remain separate. |
| Trim feel | Starting valueEnabled | What it controls and whyRetained for compatibility and group membership. Trim relief, rather than this flag, controls centre movement. |
| Trim relief | Starting valueEnabled | What it controls and whyAllows trim relief with supported control law and valid telemetry. Axis authorities set its amount. |
| Elevator Authority | Starting value0.3 | What it controls and whyTrim is documented, while the selected source does not establish its linkage to stick neutral. Pitch authority 0.3 provides load relief and permitted centre movement; roll authority is 0.1. |
| Aileron Authority | Starting value0.1 | What it controls and whyScales supported roll-trim relief and permitted centre movement. Zero removes roll response. |
| Force Trim Enabled | Starting valueDisabled | What it controls and whyEnables local force trim, separate from aircraft-owned trim and add-on integration qualification. |
| GLoad Enabled | Starting valueEnabled | What it controls and whyAllows load-factor changes to modify permitted spring laws. Passive fly-by-wire feel can suppress it. |
| Rate Damping Enabled | Starting valueEnabled | What it controls and whyEnables rate damping with the configured coefficients and control law. |
| Autopilot follow | Starting valueDisabled | What it controls and whyAutopilot following is off; the configured spring and load retain the hardware feel. |
| Autopilot follow authority | Starting value0.05 | What it controls and whySets admitted AP-follow gain, not a percentage of travel. Runtime ownership and input limits still apply. |
| Autopilot neutral hold | Starting valueDisabled | What it controls and whyPermits centering hold during a supported AP state, separate from following a moving target. |
| Autopilot neutral hold strength | Starting value0.6 | What it controls and whySets admitted AP neutral-hold strength; inactive while neutral hold is disabled. |
| Enabled | Starting valueEnabled | What it controls and whyEnables aerodynamic cues; each still needs nonzero strength and its simulator conditions. |
| Gain | Starting value0.4 | What it controls and whySets stall-buffet strength. Zero removes the cue without changing simulator stalls or warnings. |
| Gain | Starting value0 | What it controls and whySets high-Mach buffet strength; onset and full-strength thresholds are separate. |
| Gain | Starting value0 | What it controls and whySets flap buffet at the configured position and speed gates. Flap movement texture is separate. |
| Maximum flap index | Starting value1 | What it controls and whySets the final flap index for detent normalization. UP plus three detents uses maximum index3. |
| Minimum flap index | Starting value1 | What it controls and whySets the first flap detent that admits buffet; this is a handle index, not degrees. |
| Gain | Starting value0 | What it controls and whySets gear aerodynamic buffet; movement and ground-contact cues are separate. |
| Shaker Enabled | Starting valueDisabled | What it controls and whyPermits shaker at supported warning conditions; the switch does not establish aircraft equipment. |
| Stick shaker amplitude | Starting value0.5 | What it controls and whySets triggered shaker strength; inactive while the shaker feature is disabled. |
| Enabled | Starting valueEnabled | What it controls and whyEnables ground effects; each still needs its own strength and contact or motion telemetry. |
| Gain | Starting value0.3 | What it controls and whySets rolling texture strength, modified by speed, surface and undercarriage configuration. |
| Gain | Starting value0.3 | What it controls and whySets gear-bump texture during ground motion, separate from touchdown impact. |
| Gain | Starting value0.5 | What it controls and whySets landing-impact strength; landing telemetry and response shape determine the pulse. |
| Gain | Starting value0 | What it controls and whySets reverse-thrust vibration with valid reverser and engine conditions. Zero removes the cue. |
| Enabled | Starting valueEnabled | What it controls and whyEnables engine cues with nonzero settings and valid running-engine telemetry. |
| Gain | Starting value0.12 | What it controls and whySets estimated engine vibration using configured telemetry and response, not measured cockpit vibration. |
| Enabled | Starting valueEnabled | What it controls and whyEnables accessory cues with configured strengths and observed accessory movement. |
| Gain | Starting value0 | What it controls and whySets texture from observed flap movement; a command without movement does not establish the cue. |
| Gain | Starting value0 | What it controls and whySets texture from observed gear movement, separate from aerodynamic and touchdown effects. |
Limits and open questions
- Motor-glider description does not establish manual gearing.
- U15 trim authority remains unresolved.
- Follow is off; no fitted system was established.
- Wing conversion changes handling; no shared IAS force calibration was supplied.
- Two wing flight models and engine-state signals require loaded-configuration checks.
- Wing span affects roll behavior; one starting estimate does not measure both variants.
Physical validation
No physical force validation is recorded in this public catalogue for this revision. Documentary review and software checks do not establish how a particular device feels.
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